from functools import lru_cache
from pathlib import Path

from pydantic import Field, PositiveInt, model_validator
from pydantic_settings import BaseSettings, SettingsConfigDict


class Settings(BaseSettings):
    model_config = SettingsConfigDict(env_file=".env", extra="ignore", case_sensitive=False)

    admin_password: str = Field(alias="ADMIN_PASSWORD", min_length=1)
    secret_key: str = Field(alias="SECRET_KEY", min_length=16)
    credential_encryption_key: str = Field(alias="CREDENTIAL_ENCRYPTION_KEY", min_length=1)
    data_dir: Path = Field(default=Path("/data"), alias="DATA_DIR")
    database_url: str | None = Field(default=None, alias="DATABASE_URL")
    sync_interval_minutes: PositiveInt = Field(default=5, alias="SYNC_INTERVAL_MINUTES")

    @model_validator(mode="after")
    def derive_paths(self) -> "Settings":
        self.data_dir = self.data_dir.expanduser().resolve()
        if self.database_url is None:
            self.database_url = f"sqlite:///{self.data_dir / 'app.db'}"
        return self

    @property
    def tokens_dir(self) -> Path:
        return self.data_dir / "tokens"

    @property
    def activities_dir(self) -> Path:
        return self.data_dir / "activities"


@lru_cache
def get_settings() -> Settings:
    return Settings()